Turbulence, phytoplankton cell size, and the structure of pelagic food webs

This chapter explores that the pelagic food chain is mainly linear and short, and there is a relatively close coupling between the primary production and the production of (pelagic) fish in the oceans. It has been realized that pico- and nano-sized phytoplankton (e.g. cyanobacteria) and heterotrophic micro-organisms (heterotrophic bacteria, heterotrophic nanoflagellates and ciliates) play a much larger quantitative role in production and mineralization, respectively, of the phytoplankton than formerly believed. Moreover, as microbial food webs are typically long and primarily based upon regenerated phytoplankton production, microbial production contributes insignificantly to fish production in the oceans. This chapter illustrates the significance of net-phytoplankton blooms to the fisheries production in the ocean, first of all blooms associated with larger-scale physical processes, such as the major upwelling regions and the vernal temperature stratification in temperate waters.